The present invention is directed to the field of gauges employed to measure the dimensions of paper, and more specifically to a gauge for determining the dimensions, squareness and hole positions of three-hole cutsize paper.
It is well known that an important consequence of the sorption and desorption of water by paper is the change in dimension that usually accompanies changes in moisture content. The dimensionl changes originate in the swelling and contraction of the individual fibers. It has been observed that cellulosic fibers swell in diameter from approximately 15-20% in passing from the dry state to the fiber saturation point. The precise degree of swelling is impossible to predict since the paper making fibers differ considerably in this property, and because of the irregular cross-section of fibers. Even though the swelling of the fiber is caused of the expansion and contraction of the paper, there is no direct relationship between the two phenomena. Paper samples made from the same fiber and having the same fiber swelling charcteristics may exhibit a wide variety of dimensional changes, depending on conditions of stock preparation and sheet forming and drying.
The above-described changes in dimension may seriously affect register in the cutting process employed in producing cutsize paper, resulting in improper size or lack of squareness, and if the cutsize paper is of the three-hole variety, the holes drilled therein may not be provided in the proper locations in the final product.
Although commercial equipment exists which can determine cutsize paper dimensions, squareness and proper hole disposition, the prior art equipment is expensive and requires a slow, elaborate procedure and specialized operator training.